The recording devices using optical recording media, such as CD-ROM or MO are an important part for data recording. All these optical devices have an optical pickup for sending light beams to the optical recording media and receiving reflected light beams from the optical recording media. The optical pickup includes a light source, such as semiconductor laser, for emitting light beam, and a lens for focusing light beam to the optical recording media. Furthermore, the optical pickup requires an actuator for driving the lens to rectify the deviation of the focus and the lens tracking so that the light beam can be precisely focused and the recording tracks can be correctly tracked.
The majority of the actuators employ the electromagnetic method to drive the objective lens for focus and tracking deviation rectification. Therefore, a focusing coil and a tracking coil are included in the pickup devices. The focusing coil is orthogonal to the optical axis of the objective lens so that the objective lens can move up and down along the focusing direction. The tracking coil is parallel to the optical axis of the objective lens so that the lens can move along the tracking direction for rectification.
As the access speed of the optical recording media increases, the demands on the response speed and sensitivity of the electromagnetic actuator for optical pickup also increases. Taiwan Patent No. M253,044 and U.S. Pat. No. 5,627,687 both disclosed a structure of an electromagnetic actuator. However, both patents only provided focusing and tracking deviation rectification, while the tilting angle control function is not provided.